I have just moved into a new house which has a 16 way contactum consumer unit with individual mcb's for each section of the electrics in the house. I am used to the old fashioned fuse box where you take the whole fuse out to isolate that particular part of thel electrical circuit.
My question is if I flick the switch down on the correct mcb and the light goes out am i OK to contunue with changing the ceiling light or do i need to switch off the whole of consumer unit?

Colin, March 2010

Either - whichever take syour fancy - turning the whole distribution board off may/will affect heating and freezer etc

The key thing for your safety is to test and be sure - have the light you wish to tamper with switched on - throw the appropriate MCB and observe that the light has gone out - double check with a test device if you have one and if not - the light going out is a pretty sure sign that the mains power has been removed.

An MCB in the down position is just like a removed fuse.

Take care...

Peccavi, March 2010